The present invention relates generally to non binders and more particularly to case made ring binders.
Ring binders, also colony referred to as loose-leaf binders, have been used for many years to bind together sheets of paper and the like. One common type of ring binder is fabricated by heat-sealing three rigid or semi-rigid, rectangular inserts or stiflenet panels between two superimposed sheets of thermoplastic material. Of the three stiflenet panels generally used, two of them approximate in size the back and front covers of the binder and the third panel is a narrower insert disposed between the two large panels for use in forming the spine of the binder. The inner and outer plastic sheets are fused together or heat-sealed around their peripheral edges and also transversely between the adjacent, transverse edges of the cover panels and the spine panel. The transverse seals for the hinges for the binder cover and the peripheral edge seals provide the finished edges thereof. A ring binder mechanism is typically affixed to the spine of the binder cover.
Binders of the type described above are disclosed in U.S. Pat. No. 4,583,877 dated Apr. 22, 1986 to Wilson and in U.S. Pat. No. 4,600,346 dated Jul. 15, 1986 to Podosek. Although such binders are generally satisfactory for their intended purpose, they have a tendency wear over time, particularly in the hinge area and around the periphery of the binder cover where the two sheets of thermoplastic material have been used together.
Another common type of ring binder is often referred to as a case made ring binder. Case made ring binders are typically more durable and last longer than the twin thermoplastic sheet binders described above. Ordinarily, to make a case made ring binder, an oversized outer covering sheet is first wet glued onto the outer surfaces of three stiffeners arranged as a front cover panel, a back cover panel and a spine panel. The edges of the outer covering sheet are then turned over the edges of the three panels and wet glued onto the inner surfaces of the front and back cover panels. Next, a backplate having means for mounting a ring mechanism is wet glued onto the inner surface of the spine panel. A spine-reinforcing joint liner having a heat-activated adhesive on its outer surface is then affixed to the inner surface of the backplate and to neighboring portions of the front and back cover panels, as well as to the adjacent inturned edges of the outer cover sheet. Next, a pair of side liners are wet glued over the inturned edges of the outer cover sheet, as well as over portions of the joint liner and the front and back cover panels. Finally, a ring mechanism is fixedly mounted on the backplate.
One shortcoming recognized by the present inventor with case made ring binders is that the method of constructing such binders is not well-suited for automated production techniques. Consequently, such binders are typically made in production lines using the combined efforts of several different people. For example, the application of the joint liner and the pair of side liners is typically performed by three different people, with one person being responsible for applying the joint liner and two additional people being responsible for applying the respective side liners.
Another shortcoming recognized by the present inventor with such binders is that wet glue is typically used at various times in the fabrication procedure to adhere together various components. Because wet glue is typically dispensed using machines that require a great deal of maintenance, time and manpower are frequently misdirected at the cleaning of the glue machines instead of properly directed at the fabrication of binders. Another problem resulting from the use of wet glue is that several heating steps are typically required following the application of wet glue to dissipate the moisture contained therein so that a proper seal may be formed.
Patents pertaining to case made binders include U.S. Pat. No. 3,190,678 dated Jun. 22, 1965 to Peterson et al. and U.S. Pat. No. 3,277,505 dated Oct. 11, 1966 to Peterson et al.